A Vow Fulfilled
by Quicksilver985
Summary: Our story beings with the death of one of the most hated Captains. However, his killer gladly turns himself over to Soul Society's justice system. What are his motivations? And what is this vow he keeps speaking of?
1. Who Killed Kurotsuchi?

Disclaimer: Given the current fluctuations of the American and Japanese market, I refuse to speculate on whether or not I own Bleach. I will, however, give you one hint.

I am not Kite Tubo.

Make what you will of this information.

Kurotsuchi Mayuri frowned as he looked down upon the dying animal. The rabbit, with one of its lungs lying on the table next to it, gasped in pain. Mayuri sighed as he pushed the tray away and jotted something down in his notes.

"Useless animal…" he said, adjusting his mask. "Obviously this new cell structure is unable to function without oxygen." He continued to write in his journal, and did look up, even when a shadow in a corner of the room detached itself and began moving slowly towards his back. It was within feet of him when Mayuri finally spoke.

"I may not be as fond of fighting as that brute Zaraki, but please remember that I am a captain. You insult me by not thinking that I can hear you." The intruder paused.

A voice filled with regret at last spoke out.

"Kurotsuchi Mayuri, I have come here to kill you." Mayuri's pen stopped scratching at his notepad. The Twelfth Division Captain rose, and drew his zanpakuto. He would rather be studying his new work, but this stranger had irritated him.

_I am going to have to ask Nemu how this man sneaked into my office without her noticing,_ thought Mayuri as he prepared to fight. _When I get through with her, she…_ Mayuri's thought processes were suddenly interrupted by the sword sticking through his chest.

"B-b-but… how?" Mayuri had seen Yourichi herself in action, and he knew that what he had just seen was not shunpo. He saw a sad smile begin to form on the stranger's face.

"You're wondering, aren't you?" Mayuri no longer had the breath to speak, and his vision was fading. The man's face was in the light, and his features were more visible. He had jet black hair, and was slightly taller than the ryoka, Ishida Uryu. The one man who had beaten him in a fight, until now.

"You're wondering how I moved so quickly." The man began slowly walking around the captain, who felt the specter of death coming upon him. "I do not mean to be cruel, but I know how much stress it would cause you to die with an unsolved question on your mind. I made a vow," said the stranger, his eyes and mind obviously no longer on the present, "That I would treat you with the cruelty you gave to your test subjects. Farewell, Kurotsuchi Mayuri."

Though the wounded captain could no longer speak, the hate coming from his eyes could be clearly felt. As his blood seeped to the floor, Mayuri had one thought on his mind. It was not, as the stranger seemed to think, the question of how the man was in a place he clearly had not been the moment before, but something else.

_Who is this man…_

The captain went to his grave, the ultimate unanswered question, without knowing.

Kurotsuchi Nemu sat in front of her desk, filling in the mind-numbing amounts of paperwork assigned to the divisions of the Gotei Thirteen. She had long since learned not to bother Mayuri-taichou with such trivialities. Although the pain had been severe, it was far from the worst punishment she could remember at his hands.

She didn't shudder at the memory. Mayuri-taichou had punished her when she did that too.

As she was working, she began to feel that something was amiss. She kept on working, but the feeling remained like a sore at the back of her mind, become increasingly distracting. After another half-hour of working, she realized the source of the unease.

_Where is Mayuri-taichou's reiatsu? _The source of Nemu's unease having been found, she finally was able to think of solutions in the scientific, orderly method that her father had taught her.

_Could he be deliberately suppressing it?_ Nemu pondered this for a moment. She couldn't come up with a reason that her father would do something like that. There were currently no scheduled experiments that would involve such a procedure.

_Could he have left? _Nemu knew this was even more unlikely. The only way out of the lab besides the door she stood watch over was the maintenance hallway. She knew that Mayuri-taichou would consider this beneath his dignity. He would rather blow a hole in the wall and walk through it.

The more she thought, Nemu became convinced that something was wrong. She knew that she should go into the lab, but the fear of what Mayuri would do to her if she interrupted his experiment made her hesitant to enter. At long last, her fear of pain was overruled by her concern for her father. She entered the laboratory.

"Mayuri-taichou?" Nemu kept her voice at the appropriate volume, conditioned into her since her birth. "Are you in here?" All too soon, her gaze locked onto the pool of blood, and to the man lying in it.

Shock froze her to the ground. The blood drained from her face, and had she not been trained since her birth to control her emotions, she might have begun sobbing. Or laughing. She did not know. Then, her attention was drawn to the dark-haired man sitting at Mayuri's desk. Seeing that her attention was on him, he rose.

"Kurotsuchi Nemu-san," he said with a bow. "My name is Kansoki Ryaki. I am the killer of your captain. I'm afraid you'll have to arrest… oh, please don't faint."

Ryaki's words fell on deaf ears Nemu had begun falling to the floor. Before she fell, Ryuki was behind her, catching her.

_That's odd,_ she thought as she lost consciousness, _that wasn't shunpo…_

Ryuki placed her on the ground gently, making sure she had not been injured. Then, the murderer of Kurotsuchi Mayuri, the captain of the Twelfth Divison of the Gotei Thirteen, walked over to the telephone in the laboratory, and picked it up.

"Hello? Yes, please send word to First Captian Yammamoto. Tell him that Captain Kurotsuchi has been killed. By me." With that, Ryuki sat down. He did not have long to wait now. His vow had been fulfilled. Now it was just a matter of seeing what happened to him.

**Author's note: Hahahaha, I finally killed Mayuri… Now, I suppose I should finish this up in a couple of chapters. I will try…**


	2. The News Spreads

When he heard the news, Eighth Squad Captain Kyoraku Shunsui spat out his sake. Although his surprise was very real, he still had enough presence of mind to prevent spraying Ise Nanao.

"Kurotsuchi's dead?" Shunsui's mouth could have easily served as a temporary nest for low flying birds. The hell butterfly soon disappeared, its message delivered. "What do you think of that, Nanao-chan?"

Although the name would normally have irritated the fastidious vice-captain, she didn't feel that this was an appropriate time to engage in meaningless bickering. Her taichou had, after all, just lost one of his colleagues.

"I don't know, Kyoraku-taichou," she said, straightening her glasses as she spoke. "Kurotsuchi wasn't as powerful as you, or Ukitake-taichou, but he certainly wasn't a pushover. It would have taken a powerful ryoka to defeat him, especially without using enough reiatsu to attract attention.

Shunsui was about to speak, but he was interrupted by another hell butterfly. He listened to its message, the look on his normally relaxed face growing thoughtful. He nodded, and this butterfly also disappeared. He let out a sigh.

"Well, Nanao-chan, you are wrong about one thing," he said as he took another sip of his sake. "It wasn't a powerful ryoka that defeated Kurotsuchi. It was a man in a shinigami uniform."

Hitsugaya Toshirou was not outwardly fazed by the news of the Twelfth Captain's death. After thinking over the issue for a moment, the youngest captain in the Gotei Thirteen sighed and put down his pen. Matsumoto Rangiku watched him intently, waiting for his reaction. She knew that her taichou had not been particularly close to Kurotsuchi, but then again, he didn't seem very close to anyone, with the exception of Hinamori.

"Please leave, Matsumoto. I need to think about this for a while." Matsumoto looked surprised, but nodded, and left her taichou to think, alone in his office. He placed his chin in the steeple of his hands, and stared intently at his desk.

Hitsugaya had not liked Kurotsuchi. Personally, he had thought the man was manipulative and excessively cruel. However, he was a captain, the same as Hitsugaya. He would not tolerate such a blatant display of disrespect towards the Gotei Thirteen.

_This could not have come at a worse time,_ thought Hitsugaya as he prepared to go to the prison where the culprit was being held._ Now four captains are lost in the battle against Aizen._

Kotetsu Isana, the Fourth Squad Vice-Captain, let out a gasp when she heard of Kurotsuchi's murder. Unohana Retsu, however, kept her emotions in better control. The horrors of the injuries shinigami received during their duties had long since taught her the value of keeping control over her feelings. Still, inside she was reeling. Kurotsuchi, dead?

The Fourth Division, its members being among the weakest in the Gotei Thirteen, was commonly the butt of jokes among other squads. Due to this, no squad had lost more "volunteers" to Kurotsuchi's experiments. Unohana knew that she would not miss this man. However, his death did bear relevance to her. She knew that there was one issue that, if forgotten by her, would be overlooked by everyone.

With a rustling of her captain's uniform, Unohana stood up. Isana looked at her, and after a moment remembered how to speak.

"Unohana-taichou, where are you going?" Unohana looked back at her, then looked away again.

"It is all right if you remain here, Isana," said the Fourth Captain kindly. "I am going to make sure that Nemu-san is all right." She looked off into the distance, a look that Isana had long since learned to recognize as a portent of deep thought over a disturbing situation.

"The poor girl. To find the body of her father like this. I doubt she will have any idea what to do without his iron fist guiding her life."

Isana watched as her taichou left the room. She was once again reminded of Unohana-taichou's greatness. She had not given a second thought to Nemu, but now that she did, she felt an intense pity for the girl. Her entire life had been spent at the mercy of the Gotei Thirteen's cruelest captain, the man she called father. How would she learn to live her own life? Isana reluctantly began to finish the paperwork her taichou had left her, but her thoughts were not on the work.

Far away from Soul Society, in a small shop in Karakura, a black butterfly flew into the window. Soaring over a small raven-haired girl being tormented by an orange-haired brat, it sought out its target. Urahara Kisuke raised his hand to receive it.

**Author's note: Sorry if this chapter is a bit shorter than the first, I am still trying to figure out what is going to happen. Hope you all enjoy the story, and I hope you all enjoyed the death of the jerk Kurotsuchi as much as I did. I apologize if any of the characters are unintentionally OOC.**


	3. Visitation Rights

**Author's note:** **Hey, sorry for a mistake in chapter two. I meant to have lines of 's to separate the different captain's reactions, but I am still getting used to the formatting that uses. If anyone here knows how to separate sections well, please email me, or leave it in a review.**

Yamamoto left Kansoki Ryaki in the highest security jail cell in the First Squad's headquarters. The old man could not remember, in his long time spent as a captain in the Gotei Thirteen, ever having had a prisoner like Ryaki. The man had been perfectly respectful, compliant, and cooperative, yet had refused to answer any of Yamamoto's questions.

"I apologize, Yamamoto-sama," he would say. "I would rather not answer any questions until the other captains convene to decide my fate." Yamamoto had been unable to get any other response out of him.

The man's appearance alone raised questions in Yamamoto's mind. Ryaki wore a shinigami uniform, but it did not bear the insignia of any of the Thirteen Squads. However, it was not a uniform of a student in the Academy. Yamamoto intended to find out soon where this shinigami came from.

Yamamoto sighed. He knew that, like every other captain, he would not miss Mayuri. But, he knew that he couldn't tolerate this sort of crime in the midst of the war against the arrancar.

With the Room of 46 gone, it would be up to the remaining captains of the Gotei Thirteen to decide Ryaki's fate. Yamamoto intended to call the captains into a meeting tomorrow.

Nemu walked in a trance towards the jail cell. She walked through the sewers underneath Seireitei, thought to be known only to members of the Fourth Squad. However, during his many experiments, Mayuri had thought to launch of study of the underground tunnel system. He had sent Nemu to create a map, and she knew the tunnels better than anyone.

At first she had not known where she was going. She had done almost no thinking at all since she had seen her father's body on the ground. Almost immediately after she had answer Yamamoto-sama's questions, she had meandered back to the lab to look at the spot where his body had fallen. After a while, she made her way into the tunnel system and found herself under the grate that would bring her into the First Squad's jail. Not knowing what to do, she lifted the grate and climbed out.

She found herself alone in the jail. She looked around herself, and saw that all of the cells were empty. That is, all but one.

When she saw Ryaki, she didn't know what she was feeling. At first she thought it would be hate, that it was loathing telling her body to become cold and clammy, to raise goosebumps on her skin, to make her eyes begin to burn with the beginnings of tears.

Then, she thought it might have been grief, grief for her father, grief for herself. Or maybe even relief. She did not know. Without even knowing what was guiding her actions, she began walking towads Ryaki's cell.

Ryaki had his eyes closed when Nemu arrived, but he was not sleeping. He knew it would be a long time before he could sleep again. It was guilt keeping him awake. He did not feel guilt for Mayuri's death, for he knew that the man had deserved to die more than almost any other. It was guilt, guilt for a friend long since passed away, guilt he thought would be relieved with the death of the Twelfth Squad Captain. Guilt that had not ceased in the least with the fulfillment of his vow.

Lost in his reflections, and his memories of that night eighty years ago, Ryaki didn't hear Nemu until she had reached his cell. Even had he not been aware of her presence by then, however, he would surely have noticed the noise when she drew her sword and cut through the bars of his cell.

Ryaki did not have his zanpakuto with him, having relinquished it to the shinigami who came to arrest him. Even if he had had it, however, he would not have raised it against this woman. He knew who Nemu was, and knew what she must have been going through. Perhaps even better than she did.

He did not move to dodge as she came at him with her sword raised. He showed no fear in the rapidly approaching face of death, the face that manifested itself in Nemu's blank visage, in her confused eyes.

He did, however, show surprise when Captain Hitsugaya and his zanpakuto were suddenly between him and Nemu.

Nemu had seen the bankai of Hitsugaya Toshiro, had seen its icy glory destroy entire groups of hollow. However, she knew that right now, Hitsugaya's eyes were colder than Hyorinmaru had even been. Nemu knew, suddenly, that she had committed the worst sin imaginable, in Mayuri's eyes.

She had lost control.

Nemu had always been watched over by Mayuri. Although he had been far from a loving father, he had provided her with guidance, with rules, with objectives. She had been with this guidance her whole life, and she knew now that in the absence of Mayuri's watchful eyes, she has lost control.

Oblivious to Hitsugaya, Nemu fell to her knees. She began to do something that shook Ryaki, who had been firm in his resolve. It warmed the eyes of the Tenth Squad Captain.

Kurotsuchi Nemu, the daughter of Kurotsuchi Mayuri, began to cry.


End file.
